(a) Technical Field
The present invention relates to a high voltage system of an electric vehicle. More particularly, it relates to a high voltage system of an electric vehicle which makes it possible to eliminate a sub-battery by providing a high voltage battery that can function as the sub-battery.
(b) Background Art
In general, electric vehicles refer to those which utilize electricity for power to a large extent, and an HEV (Hybrid Electric Vehicle), a PHEV (Plug-in Hybrid Electric Vehicle), and an EV (Electric Vehicle) are typical electric vehicles.
As shown in FIG. 1, a high voltage system of an electric vehicle includes a high voltage battery 1, an inverter, an LDC 2, an electric compressor, and a high voltage motor 4. As further shown, a sub-battery 3 (e.g., a lead-acid battery of 12V) is further used, in addition to the high voltage battery 1, to operate common electric equipment, except for high voltage components which are generally operated by the high voltage battery.
In an electric vehicle, the sub-battery 3 is generally (1) used after charging it with the power source of the high voltage battery using LDC 2, (2) used to operate common low voltage electric equipment, or (3) used to control relay-on/off in starting the vehicle.
As described above, the high voltage battery 1 of a high voltage system of an electric vehicle according to the related art always receives power from the sub-battery 3 for relay-on/off in starting the vehicle and for the low voltage electric equipment (see FIG. 2). Accordingly, an additional space is required for accommodating the sub-battery 3. As a result, space availability is reduced and layout becomes difficult.
Further, since the life span of the sub-battery is relatively short, it becomes necessary to replace a plurality of batteries while using the vehicle. This results in additional costs over time.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.